Module reference
9.1 Cache
9.2 Decode
9.3 File
9.4 Pagetree
9.5 Render
9.6 Template
9.7 Tag
9.8 Top
9.9 World
On this page:
->html
select
select*
select-from-metas
select-from-doc
6.0.1.11

9.6 Template

 (require pollen/template) package: pollen

Convenience functions for templates. These are automatically imported into the eval environment when rendering with a template (see render).

This module also provides everything from sugar/coerce/value.

procedure

(->html xexpr    
  [#:tag html-tag    
  #:attrs html-attrs    
  #:splice splice-html?])  string?
  xexpr : xexpr?
  html-tag : (or/c #f txexpr-tag?) = #f
  html-attrs : (or/c #f txexpr-attrs?) = #f
  splice-html? : boolean? = #f
Convert xexpr to an HTML string. Similar to xexpr->string, but consistent with the HTML spec, text that appears within script or style blocks will not be escaped.

Examples:

> (define tx '(root (script "3 > 2") "Why is 3 > 2?"))
> (xexpr->string tx)

"<root><script>3 &gt; 2</script>Why is 3 &gt; 2?</root>"

> (->html tx)

"<root><script>3 > 2</script>Why is 3 &gt; 2?</root>"

The optional keyword arguments html-tag and html-attrs let you replace the tag and attributes in the generated HTML.

Examples:

> (define tx '(root ((id "huff")) "Bunk beds"))
> (->html tx)

"<root id=\"huff\">Bunk beds</root>"

> (->html tx #:tag 'div)

"<div id=\"huff\">Bunk beds</div>"

> (->html tx #:attrs '((id "doback")))

"<root id=\"doback\">Bunk beds</root>"

> (->html tx #:tag 'div #:attrs '((id "doback")))

"<div id=\"doback\">Bunk beds</div>"

The splice-html? option will strip the outer tag from the generated HTML.

Examples:

> (define tx '(root (p "Orange marmalade")))
> (->html tx)

"<root><p>Orange marmalade</p></root>"

> (->html tx #:splice #t)

"<p>Orange marmalade</p>"

Be careful not to pass existing HTML strings into this function, because the angle brackets will be escaped. Fine if that’s what you want, but you probably don’t.

Examples:

> (define tx '(p "You did" (em "what?")))
> (->html tx)

"<p>You did<em>what?</em></p>"

> (->html (->html tx))

car: contract violation

  expected: pair?

  given: "<p>You did<em>what?</em></p>"

procedure

(select key value-source)  (or/c #f txexpr-element?)

  key : symbolish?
  value-source : (or/c hash? txexpr? pagenode? pathish?)

procedure

(select* key value-source)  (or/c #f (listof txexpr-element?))

  key : symbolish?
  value-source : (or/c hash? txexpr? pagenode? pathish?)
Find matches for key in value-source, first by looking in its metas (using select-from-metas) and then by looking in its doc (using select-from-doc). With select, you get the first result; with select*, you get them all. In both cases, you get #f if there are no matches.

procedure

(select-from-metas key meta-source)  (or/c #f txexpr-element?)

  key : symbolish?
  meta-source : (or/c hash? pagenodeish? pathish?)
Look up the value of key in meta-source. The meta-source argument can be either a set of metas (i.e., a hash) or a pagenode?, from which metas are pulled. If no value exists for key, you get #f.

Examples:

> (module ice-cream pollen/markup
  '(div (question "Flavor?")
    (answer "Chocolate chip") (answer "Maple walnut"))
    '(meta ((template "sub.xml.pt")))
    '(meta ((target "print"))))
; Import doc & metas from 'ice-cream submodule
> (require 'ice-cream)
> (select-from-metas 'template  metas)

"sub.xml.pt"

> ('target . select-from-metas . metas)

"print"

> (select-from-metas 'nonexistent-key metas)

#f

procedure

(select-from-doc key doc-source)  (or/c #f txexpr-element?)

  key : symbolish?
  doc-source : (or/c txexpr? pagenodeish? pathish?)
Look up the value of key in doc-source. The doc-source argument can be either be a doc (i.e., a txexpr) or a pagenode?, from which doc is pulled. If no value exists for key, you get #f.

Examples:

> (module gelato pollen/markup
  '(div (question "Flavor?")
    (answer "Nocciola") (answer "Pistachio"))
    '(meta ((template "sub.xml.pt")))
    '(meta ((target "print"))))
; Import doc & metas from 'gelato submodule
> (require 'gelato)
> (select-from-doc 'question  doc)

'("Flavor?")

> ('answer . select-from-doc . doc)

'("Nocciola" "Pistachio")

> (select-from-doc 'nonexistent-key doc)

#f